Roof-Mounted Temperature Sensing With Dual Sensors Against Sunlight Error
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Solution Overview
Problem
Existing temperature measuring devices for air conditioning systems in motor vehicles are susceptible to errors due to direct sunlight exposure, which can lead to inaccurate interior temperature readings.
Innovation Solution
A compact temperature measuring device featuring a thermally conductive cap and a flexible circuit board with two spatially spaced temperature sensors, eliminating the need for a photodiode and ensuring reliable temperature measurement by positioning the device in a location protected from direct sunlight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a temperature sensor is positioned to measure interior temperature, then temperature control capability is improved, but measurement accuracy deteriorates when exposed to direct sunlight
Solution Approach 1:
The temperature measuring device is segmented into multiple temperature sensors positioned at different locations. At least one sensor is placed on the circuit board away from the cap to measure ambient temperature, while another sensor measures cap temperature. This segmentation allows the system to differentiate between sunlight-heated cap temperature and actual ambient temperature, resolving the contradiction between measurement accessibility and accuracy.
Solution Approach 2:
The circuit board acts as an intermediary thermal element between the cap and the temperature sensors. By positioning sensors on the circuit board at strategic locations, the system uses the circuit board's thermal properties to transmit and differentiate temperature information, enabling accurate ambient temperature measurement even when the cap is exposed to sunlight.
2Measurement precision
If a photodiode is used to detect sunlight exposure, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The photodiode component is completely removed from the device. Instead of using optical detection, the invention extracts only the necessary thermal measurement function by positioning temperature sensors on the circuit board to directly measure ambient temperature, eliminating the need for complex optical detection mechanisms while maintaining measurement accuracy.
Solution Approach 2:
The optical detection mechanism (photodiode) is replaced with a thermal measurement approach using temperature sensors on the circuit board. This substitution uses thermal fields instead of optical fields, simplifying the device by eliminating the photodiode while achieving the same goal of accurate temperature measurement through direct thermal sensing.
3Volume of moving object
If multiple temperature sensors are positioned close together, then device compactness is improved, but thermal interference between sensors increases
Solution Approach 1:
Different regions of the circuit board are assigned different thermal measurement functions. Sensors are positioned at specific locations with different thermal characteristics - one sensor measures cap temperature while another measures ambient temperature through the circuit board. This local differentiation allows compact positioning while maintaining measurement reliability through spatial thermal zoning.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides accurate and reliable temperature measurement inside a motor vehicle, even without a photodiode, by utilizing a thermally conductive cap and flexible circuit board design that is not exposed to direct sunlight, thus enhancing the reliability of air conditioning system control.
Implementation Method 1
The temperature measuring device has a thermally conductive cap (8) and a circuit board (9), which is coupled to the thermally conductive cap (8) in a partial area (13) of the circuit board
Implementation Method 2
a first temperature sensor (10), which is arranged on the circuit board (9) in the partial area (13) on a second side (26) opposite the first side (25) and is configured to detect first temperature information
Implementation Method 3
a second temperature sensor (11), which is arranged at a spatial distance from the first temperature sensor (10) on the circuit board (9) and is configured to detect second temperature information
Implementation Method 4
The temperature measuring device has an evaluation unit (14), which is configured to determine a temperature value by applying an evaluation criterion to the detected first and second temperature information
Data Source
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AI summary
The invention relates to a temperature-measuring device (4) for an air-conditioning installation (2) of a motor vehicle (1), to a roof-mounted controller (3), having the temperature-measuring device (4), for the motor vehicle (1), and to a system (5) comprising the air-conditioning installation (2) and the roof-mounted controller (3). The temperature-measuring device (4) has a thermally conductive cover (8) and a flexible circuit board (9) having two temperature sensors (10, 11) that are arranged on the circuit board (9) in a manner spatially spaced from one another. The roof-mounted controller (3) additionally has a central circuit board (27) that is connected to the flexible circuit board (9) of the temperature-measuring device (4) by way of a connecting element (28). A capacitive input element (20) for the roof-mounted controller (3) may for example additionally be connected to the flexible circuit board (9).